Thanks! I'll try that and post back.
One small detail that was mentioned in my lengthy list of details was the fact that with the CLI command for xa-data-source I could find no way to provide the URL connection. In the original *-ds.xml file, this was specified as
<xa-datasource-property name="URL">jdbc:oracle:thin:@localhost:1521:XE</xa-datasource-property>
But with the CLI command I could not find its corresponding option. There is a connection URL option/parameter for the regular data-source CLI command, but not one for the XA version. Any ideas?